US1754645A - Electric motor - Google Patents

Description

A. E. OSWALD ELECTRICl MOTORv April 15, 1930.

Original Filed Nov. 30, 1920 Patented Apr. 15, 1930 Parana erica ALFRED n. oswA'Ln, or iiAeir'nnsneK, new

JnRsiii'Y, Assis-Non To U'Nnnnwoon nm'orfr 'rrsnnn centran?, 'anw renie it. Y., Genre-'naaien or DELAWARE ELECTRIC MOTOR 'Original application led November 30, 192D, Serial No. 427,846. Divided and this application 'led August 18, 1925.

This invention `relates to terminals oonnecting boards for electric motors, and one of its main objects is to adapt the motor for work under a wide variety of conditions, thereby substantially increasing its range of usefulness. Y

Many Vof the improvements relate to termilarl connecting boards for the use of vthe motor only with alternating current; but provision is also lmade for adapting it by `other terminal connections into a direct current motor Without substantially changing the saine. The motor, supplied with suitable terminal connecting boards, may be used for any commercial frequency and a great range of voltage. The adaptation of the motor for different cireuitsinay be made'by an inesperienoed person. This invention has greatvalue (ir motors of less than one horsepower, although the invention is not limited thereto. The number of motors that a manufacturer needs Yto produce in order to meet widely varying demands may -be greatly reduced.

For alternating current l employ a coinmutator, which connects the rotating armature in series with novel stationary auxiliary coils, and l control the speed by mea-ns of a novel relationship between the armature auxiliary coils and field coils. The field coils are in shunt around both the armature and :uiniliary coils, the last being electrically opposed L.to the field coils,` and act-ingl in conjunction with "a novel cor in a manner to render the rotor self-corrective as to speed under varying loads. problem `of adapin the 'motor p is solved by Winding for thevhighest freeyand connecting Vthe field coils, and 4o insa the auxiliary coils, in pa alle'l, series or fvtlieiivise. 'Elie motor adapted fordifferent voltages in altern.atingl work, by further modifying or rearranging `the relation ship between the coils `or sub-coils; `numereus combinations being; feasible. The desired rate of rotation is-secured by certain modifications of suoli arrangements.

It .is usual to Wind motors differently for different frequencies, so that a motor Athat is Wound for one circuit-cannot be successfully for dili'eront frequencies Serial No. 50,928.

used on another circuit having` a different frequency. Therefore, it is necessary for a dealer to keep agr'eat variety of motors in stock. One of the objects of the invention is to Iproduce a motor that will successfully operate in differentcircuits having diiferent frequencies. o

i lt is usual also to Wind motors differently for use yWith circuits having different voltages, and this also makes it imprac'ticable to use the same motor on different circuits, and further makes it necessary to vkeep a variety of motorsy in stock. Since also the voltage varies in different circuits having the same frequency,A a further lcomplication ensues; and it has been necessary, therefore, to keep a very large variety of motors insteek. One of the objects yofthis invention -is to overcome this difficulty also, and to `provide means whereby a motor can be used for cireu-its having different voltages; and the improvement is carried so far that the motor `can be used Withv circuits having` different frequencies as Well different voltages for the same frequency.

This invention provides means whereby the motor can be used Iwith an alternating current not only for 4different frequencies and different voltages, but also for different speeds, as may be required, thereby still further en-larging the field of usenlnessl of the invention and making possible stil-l further .reduction in the assortment of motors that it is necessary to Carry in stock.

One feature ofimprovement Iis the facility and-certainty with which the connections can be changed, even byone unfamiliar With the iinator.y There-is provided inthe motor-frame aboard or plate-on Which isarranged a full set of terminals lfor the different coils, the armatureand the resistance. Upon a separate board or plate attached thereto' and removable therefrom, are arranged the necessary contacts having appropriate connections for the Work in hand. Each removabley contact plate may bejmarlied'to indicate the `Work that will be performed by the motor when s id plate is fastenedthereto. An assort# .rent of these ren-lovabley plates maybe kept in stock, so 'that when. i dealer IlCeves an order for a motor for either alternating or direct current, and for a certain frequency and a certain voltage and speed, he needs only to select the plate which is marked for such current, frequency, voltage and speed, and secure the same upon the motor, whereupon itis ready for the customers use.

This is a division of my application Serial No. 427,346, filed November 30, 1920 (new Patent No. 1,554,647, dated September 22, i925).

Other features and advantages will hereinafter appear.

ln the accompanying drawings,

Figure l is a View of the end portion of the motor frame, to illustrate a terminal board or plate mounted therein, for use with any of the Contact plates seen at other figures.

AFigure 2 is a cross-section, Figure 8 is a tcp plan and Figure 4 is an inverted plan of one form of contact plate to be fastened to the machine, with its contacts for engaging the terminals seen at Figure 1, whereby the motor is alterable for use with direct current, 1530 volts.

Figure 5 is a fragmentary sectional view to illustrate in cross-section the arrangement of the contact plate seen at Figure 1.

Figure 6 is a diagram of the connections when the motor is to be used for direct curent, 50 volts.

Fi gure 7 is an inverted plan of the contact plate which is screwed in place in the end of the motor to producethe connections seen at- Figure 6, thereby altering or converting the motor as explained in connection with Figure 6.

Figure 8 is a diagram of the connections when the motor is to be used for alternating current, 40 cycles, 130 volts.

Figure 9 is an invert-ed view of the companion contact plate.

Figure 10 is a diagram of the connections when the motor is to be used for alternating current, 120 volts, 60 cycles. The saine diagram can be used when both the voltage and the cycles are doubled, that is, 240 volts and 120 cycles; and the same rule applies to the other diagrams.

Figure 11 is a companion diagram of the` contact plate.

Proceeding from the foregoing general statements to a more detailed description, the motor shaft isseen at 40, Figure 5, carrying rin armature 41, comprising standard windin Us suitable for alternating current, or fewer than would be the case with a corresponding direct current motor. The core of the armature is laminated. Said shaft is journaled in bearings 44 carried by spider-like heads 45 of the framework, which latter also conia barrel.A drum or casing 46. The armais provided with. a commutator 47 to cc-operate with brushes, not shown.

The field of the motor is wound with; a

plurality of coils including a set of main field coils 49, 50, 51 and 52, and a set of auxiliarycoils 66, 67, 68, 69, 70, 71, 72 and 7 3, diagrammatically shown in Figures 6, 8 and 10 of the drawings, and which are more specifically referred to in my Patent 1,554,647, dated September 22, 1925.

At Figure 5 is shown a section of a terminal plate 83 of insulating material secured upon the inner side of the head by means of screws 84; spacing collars 85 being placed upon the screws to position the terminal plate v83 well within the head, so as to accommodate a contact plate or block 86, see Figures 2 and 3, which is removable and hence omitted from Figure 5. The terminals on the plate 83 are in the form of heads 87 formed on posts 88 in the terminal plate which are connected to the ends 89 of the various windings or coils. T he arrangement of the terminals in the terminal plate is seen at Figure 6, which also shows a diagram of the coils, etc., the commutator terminals being indicated at 90. Appropriate contacts 91, see Figure 2, project from the contact plate 86, which includes an insulating block 92 to which they are secured by copper rivets 93, the heads 94 of which may be electrically connected by wires 95 in various ways to meet various requirements. The block 92 may be secured to the bottom of a plate 96, Figure 2, which, together with the top of the contact plate 86, may form av box having sides 97 and ends 98 to contain the wires 95 and heads 94. Screws 99 may pass down through holes 100 in the cover plate 86 and the bottom plate 96 and thread into holes 101, Figure 5, in the head 45 of the motor casing for detachably securing the contact plate in position with the contacts 91 engaging the appropriate terminal heads 87.

At Figure 6, which shows connections for direct current volts, the field coils 49, 50 are in series with each other and in parallel with the field coils 51, 52, the latter being also in series with each other, thereby Inaking a semi-parallel field of lower resistance, suitable for the low voltage. For the same reason the auxiliary coils 66 to 69 are connected in parallel with the auxiliary coils to 73 .throughout the diagram; that is, 66 to 69 are all in series, and the same is true of 70 kto 73. These auxiliary coils are always connected up to help the field coils for direct current, and are in series with the armature 41in all the drawings. At Figure 6 and in all the remaining diagrams, is shown a resistance comprising coils 102, 103, 104, 105, but for thelow volta-ge of 50 none of this resistance is needed. If the voltage were increased to 60, then coil 102 would be cut in, and so on for higher voltages.

At Figure 7 is shown an inverted plan of the contact plate for copperating with the set of terminals 87 to effect the connections may be made in the connections to suit the re uirements of the case in hand.

igure l shows the terminal plate in place in the head of the motor and ready for t-he attachment thereto of any of the contact plates seen in the various diagrams. The coils are indicated diagrammatically.

Figure lshows a contact plate that may be employedl for connecting up the coils for direct current, 130 volts; the eld coils being all in series, so as to secure enough windings to give the proper resistance. In other respects the connections may be the same as at Figures 6 and 7. The wire 121 at Figure 4 connects to the opposite ends of the rheostat from the permanent wire 106, the entire resistance being in series with the armature, on account of the increased voltage.

It will be understood that to produce a motor that can be used forcircuits having different voltages and different frequencies, as well as different voltages for the same frequency, the coil connections may be shifted. For lowest voltage the coils may be connected in parallel so as to keep down the inductance and resistance and enable the motor to take the desired power from the line. For highest voltage the coils would be connected in series so as to secure great inductance and resistance and prevent the motor from taking too much current. F or different combinations of frequency and voltage, a corresponding combination of coils may be employed. In a circuit having high frequency and low voltage, the coils may all be in parallel. For low frequency and high voltage, they may all be in series. For other combinations of frequency and voltage, there are used corresponding connections of the coils. These combinations may be numerous and provide for the usual combination of voltage and frequency. There might be 30 or more combinations of the coils; but the windings remain always :the same, and in all cases all of the field and armature windings may be used.

vIt will be understood that by substituting contact plates, the D. C. arrangement illustrated at -Figure 6 may be used for voltages of from 85 down to 45. The A. C. arrangement a-t Figures 8 and 10 may likewise be used for circuits having different frequencies and voltages, the higher the voltage the greater the number of cycles as a general thing. 1

It will thus be seen that inpracticing cer tain of the improvements, only a few motors need be kept in stock, w-hereas a great variety of wants may be readily supplied by merely keeping in stock an assortment of relatively simple and inexpensive contact plates. C nfusion and mistakes in the use of the plates are avoided because each one may be plainly marked with the appropriate designations.

It will also be seen that where the owner of a motor has occasion to use the same in a different circuit or for different speed or frequency, etc., he needs only to secure from the dealer an appropriate plate and substitute it for the old plate on the motor, Where upon it is ready for use in the new environment, thus avoiding the necessity of purchas- A Each contact plate may be regarded as a motor-adapter, whereby the motors are adapted to operate in a manner and from a circuit corresponding to the arrangement of the connection-s on each plate. It is obvious that the complete set of contact plates constitute motor-adapting means whereby the owner of the motor is enabled to selectively adapt the motor to various circuits or for various characteristics of motor operation. Variations may be resorted to within the scope of the invention, and portions of the improvements may be used without others. Having thus described my invention, I claim: K

l. As a new article of manufacture, the combination of a plate of insulating material, electrical contacts mounted thereon for electrically engaging the terminals of the armature coils, field coils and auxiliary coils of a convertible motor, wires supported on the plate electrically connecting the contacts together, and a separate plate secured over said contact-plate and forming therewith a box having top, sides and ends constituted of said separate plate and a bottom constituted of the contact-plate, said box enclosing said wires.

2. A motor-adapter including an insulating member, provided with contacts, having interconnectible terminals, said contacts corresponding to the several terminals of a motor of the charac-ter herein described, a box or device forming a protective covering for said contact-terminals, certain contact-terminals being electrically connected with others in a predetermined arrangement, whereby, upon attachment of said motoradapter to said motor, said motor is automatically adapted to operate in a manner and from a circuit corresponding to said predetermined arrangement.

ALFRED E. OSVALD.

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